JPH11211763A - Radio wave data measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio wave data measuring apparatus for analyzing a frequency and a pulse with one system constitution, easily altering a compression ratio by enlarging a frequency to be analyzed. SOLUTION: The ratio wave data measuring apparatus comprises an A-D converter 5 for A-D converting a radio wave to be measured, a digital memory 11a for sampling an output of the converter 5 at a first sampling time interval and storing it, a D-A converter 1 for reading the stored sampled value and converting it into an analog value, a frequency analyzer 9 for frequency analyzing the D-A converted sampled waveform after frequency compression, and a pulse data analyzer 11 for sequentially altering the first sampling time to a pulse width detecting time variable, storing an amplitude waveform analyzed by the frequency analyzer at each pulse width detecting time variable value and analyzing the pulse width and a pulse repeating frequency. Thus, the stored sampled value is group D-A converted at a predetermined increasing or decreasing time interval.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention
The present invention relates to a radio wave specification measuring device for measuring the frequency and other radio wave specifications of the radio wave.

[0002]

2. Description of the Related Art FIG. 7 shows a conventional radio wave specification measuring device. In the figure, reference numeral 1 denotes an antenna for receiving a radio wave having a frequency f propagating in a space, and 15 denotes a frequency f1 for converting a received radio wave into a frequency-modulated intermediate frequency.
A swept local for generating a reference signal frequency-modulated from f to f2; a mixer 3 for synthesizing the received radio wave and the reference signal from the swept local 15 to generate an intermediate frequency frequency-modulated from the frequency f-f1 to f-f2; Reference numeral 4 denotes a broadband filter for limiting the intermediate frequency converted by the mixer 3 and converted in a wide band, 8 denotes a distributed delay line that compresses the intermediate frequency and converts frequency information to a time axis region, and 9 denotes a distributed delay line. This is a frequency analyzer that analyzes the output and measures the frequency with high sensitivity. Although the apparatus shown in FIG. 7 measures only the frequency specifications, the apparatus shown in FIG. 8 has a narrow band characteristic that can be measured with high sensitivity in order to measure the pulse width and the pulse repetition period. It is common to use a radio wave measurement system of another system with. The frequency analyzer 9 has a configuration in which a detector 9a and a time measurement / calculator 9b are cascaded. FIG. 9 is a diagram for explaining the operation of the apparatus having the configuration shown in FIG.

Next, the operation will be described with reference to FIG. The radio wave of the frequency f arriving at the radio wave specification measuring device is received by the antenna 1, distributed to two paths by the distributor 16, and input to the mixer 3 respectively. In the sweep local 15, a reference signal having a sawtooth frequency characteristic that changes with time T from a frequency f1 to a frequency f2 shown in FIG. 9B is generated and input to the mixer 3. The mixer 3 outputs a sawtooth-like intermediate frequency that changes with time T from the frequency f-f1 to the frequency f-f2 shown in FIG. 9C from the received radio wave and the reference signal. Input to the distributed delay line 8. The distributed delay line 8 has a delay time-frequency characteristic shown in FIG. 9D, and the input intermediate frequency is compressed to a characteristic as shown in FIG. 9E. The compressed signal is input to a frequency analyzer 9 where it is detected by a detector 9a at a preceding stage, and a center amplitude of the signal compressed from a sawtooth starting point t0 of an intermediate frequency by a time measuring / calculator 9b at a subsequent stage is output. The time Tx until the operation is performed is measured. Here, since the delay time-frequency characteristic of the distributed delay line 8, the frequency characteristic of the sweep local 15 and the Tx are known, the unknown frequency f is calculated by the time measuring device / calculator 9b by the following equation (1). ,
The frequency which is one of the radio wave specifications is obtained. f−f1 = f0 + (1−Tx / T) × (fy−f0) (1) On one path, the pulse width and pulse specifications are analyzed by narrow-band temporal analysis of the vicinity of the measured frequency. Get. That is, the reference signal of the local 2 is adjusted by the frequency data of the frequency analyzer 9, and the intermediate frequency generated by the mixer is removed by the narrow band filter 17 to remove unnecessary noise and the like.
Other radio parameters such as a pulse width and a pulse repetition period are obtained by the radio parameter measuring device 18.

[0004]

The conventional radio wave specification measuring apparatus is configured as described above, and the sweep local of frequency modulation has a saw-tooth characteristic. You can't get anything but information. Therefore, in order to measure radio wave characteristics with high sensitivity, two systems are required: a broadband system that measures frequency, and a narrow band system that measures radio wave characteristics such as pulse width and pulse repetition period based on the information. There was a problem that was. In addition, since the characteristics of the distributed delay line are constant with the same hardware, there is another problem that it is not easy to change the compression ratio for narrowing down the target frequency by changing the frequency in various ways.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide an apparatus capable of measuring important radio parameters such as frequency, pulse width, and cycle with high sensitivity by using a single system. And It is another object of the present invention to obtain a device in which the compression frequency and the like can be arbitrarily changed and the target frequency is widened.

[0006]

The radio wave specification measuring apparatus according to the present invention is characterized in that an input radio wave to be measured is frequency-converted, frequency-analyzed, and pulse-analyzed. A / D converter for analog / digital (A / D) conversion, a digital storage unit for sampling and storing the output after the A / D conversion at a first sampling time interval, and a storage value for the stored sampling value. , A D / A converter for reading out and converting it to an analog value, a frequency analyzer for frequency-analyzing the D / A-converted sampled waveform after frequency compression, and a pulse width for sequentially changing the first sampling time The amplitude waveform analyzed by the frequency analyzer is stored for each pulse width detection time variable value as a detection time variable, and the pulse width and the pulse repetition period are analyzed. It includes a scan specifications analyzer, and adapted to convert the group D / A and the stored sampled values in a predetermined increase time or decreasing the time interval.

Furthermore, in digital storage, sampling and storage are performed at predetermined increment or decrement time intervals, and D / A conversion is performed at equal intervals.

Further, the pulse specification analyzer converts a frequency component obtained by subjecting the sampling value stored in the digital storage unit to a fast Fourier transform, by sequentially changing the first sampling time to obtain a pulse width detection time variable. The amplitude waveform analyzed by the frequency analyzer is stored for each pulse width detection time variable value, and the pulse width and the pulse repetition period are analyzed.

Furthermore, in place of D / A conversion and frequency compression, a frequency component obtained by subjecting a sampling value stored in a digital storage unit to a fast Fourier transform, and a reference circuit output in which a reference function after the Fourier transform is set are set. Using a digital compressor that performs multiplication, a frequency component obtained by performing a fast Fourier transform on the sampling value stored in the digital storage unit is used as a time variable for pulse width detection by sequentially changing the first sampling time, and the frequency analysis is performed. The amplitude waveform analyzed by the detector is stored for each pulse width detection time variable value, and the pulse width and the pulse repetition period are analyzed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, an apparatus according to Embodiment 1 of the present invention, in which all important radio wave parameters can be measured by one system, will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes an antenna for receiving a radio wave propagating in space;
Is a local that generates a reference signal to convert a received radio wave into an intermediate frequency, 3 is a mixer that combines the received radio wave and a reference signal from the local 2 to generate an intermediate frequency, and 4 is a wideband filter that removes unnecessary frequency components. Reference numeral 5 denotes an A / D converter for converting an intermediate frequency into a digital value, and 6 denotes a DRFM (Digital Radii) for storing the digital value.
o Frequency Memory), 7 are D / A converters for converting a digital quantity into analog at an externally designated sampling interval. These DRFM 6 and D / A converter 7 operating at a designated variable sampling interval are important components. Element. Reference numeral 8 denotes a dispersion type delay line that compresses the modulated intermediate frequency to increase the sensitivity, and 9 denotes a frequency analyzer that analyzes the output of the dispersion type delay line and measures the frequency with high sensitivity. Reference numeral 11 denotes a pulse specification analyzer, which internally has an amplitude distribution storage unit 11a corresponding to a frequency, and a peak amplitude time length and carry-over time (reciprocal to period) calculator 11b. FIG. 2 is a diagram for explaining the operation of the device having the configuration shown in FIG. FIG. 3 is an operation explanatory diagram showing frequency versus amplitude characteristics with different sampling times.

Next, the operation will be described. The radio wave received by the antenna 1 is combined with the reference signal generated in the local 2 by the mixer 3 and converted into an intermediate frequency. Then, after removing a signal in a band different from the signal received by the wideband filter 4, the signal is sampled by the A / D converter 5 at a sampling period T and converted into a digital amount.
Will be recorded. The DRFM digitally samples and stores the received radio wave at a period sufficiently shorter than a half wavelength of the received radio wave to be measured. Then, the stored contents can be reproduced as needed. In the present embodiment, in the case of pulse analysis, the stored received radio wave may be reproduced as it is, or in the case of frequency analysis, the pulse interval is sequentially widened and reproduced, and the frequency analysis is performed by changing sampling points described later. repeat. After that, in the process of converting the DRFM 6 to an analog waveform by the D / A converter 7, as shown in FIG. 2B, 3T, 2T, 3T, 4T
.. The time interval is sequentially increased with Tx, and the data of DRFM6 is thinned out and extracted. This is equivalent to performing frequency modulation, which means that an intermediate frequency similar to the intermediate frequency having the frequency modulation generated using the swept local is generated. This signal is compressed at the intermediate frequency by the dispersion type delay line 8 to generate a peak, and the peak is analyzed by the frequency analyzer 9 to obtain a frequency.

According to the above operation, an amplitude distribution obtained by modulating the frequency is obtained, and thus the frequency is determined from the peak amplitude. In FIG. 3, for example, Xscc
Then, an amplitude distribution is obtained for the frequency axis at. Therefore, if the data stored in the DRFM is shifted by the sampling period Tsec or nTsec (n is an integer) of the DRFM and the frequency distribution is similarly analyzed, the data is shifted by Tsec or nTsec as shown in FIG. Compressed data can be obtained. From this frequency distribution for each time, the calculator 11b finds the time change of each compression peak,
The frequency / radio wave spectrometer can measure radio wave parameters such as pulse width or pulse repetition period. With the configuration described above, the radio wave parameters such as the pulse width or the pulse repetition period can be measured with high sensitivity locally in one system. With the above configuration, even if the target frequency is wide, the DRF
By changing the sampling interval for M6 data extraction, the modulation cycle and modulation width of frequency modulation can be easily and significantly converted.

Embodiment 2 FIG. In the first embodiment, the DRFM6
Was transferred to the D / A converter 7, the frequency was compressed. As shown in the configuration of FIG. 4, the sampling cycle is changed using the A / D converter 10 capable of converting the sampling cycle. May modulate the intermediate frequency,
The same result as in the first embodiment is obtained. That is, at the time of A / D conversion, the sampling cycle variable A / D modulator 10 performs sampling which is sequentially thinned out in FIG. 2B and performs A / D conversion. With the above configuration, it is not necessary to perform the thinning of the address of the storage signal of the DRFM, and it can be realized only by the timing control of the A / D converter 10, so that the modulation period and the modulation width can be more easily converted. The measurement of the pulse width and the pulse repetition period is performed in the same manner as in the first embodiment.

Embodiment 3 A method for obtaining radio wave parameters such as a pulse width or a pulse repetition period by another method will be described. As described above, even if the frequency distribution is obtained by another method, the pulse width and the pulse repetition period can be obtained by detecting the peak amplitude whose time axis is shifted by the method shown in FIG. In the above embodiment, the radio wave data of the pulse width and the repetition period were measured by compressing the data in the DRFM a plurality of times, but as shown in FIG. 5, the data in the DRFM was converted into 12 (fast Fourier transform). The frequency characteristics may be derived by an FFT circuit. The data in the DRFM may be shifted by Tsec or nTsec (n is an integer), and a plurality of frequency characteristics may be derived by the FFT circuit and analyzed by 13 radio wave specification analyzers. As a result, a result similar to that of the above embodiment can be obtained. The frequency analysis is the same as in the first embodiment. Note that the present embodiment and Embodiment 2 may be combined.

Embodiment 4 A method for obtaining the frequency distribution by another method will be described. In the first embodiment, compression is performed by performing D / A conversion after A / D conversion, returning to an intermediate frequency, and then passing through a distributed delay line 8. In the present embodiment, as shown in FIG. 6, 14 digital pulse compressors are provided in place of the D / A converter 7 and the distributed delay line 8, and the digital data is directly compressed.

Next, the operation will be described. In the configuration shown in FIG. 1, the waveform input to the distributed delay line 8 is x1 (t)
And the impulse response of the distributed delay line is h (t)
In this case, the output x2 (t) of the distributed delay line is expressed by the convolution (convolution) of x1 (t) and h (t) in the following equation (2).

[0017]

(Equation 1)

Here, X1 (f) is an X (t) Fourier transform type, and h (f) is a h (t) Fourier transform type. By the way, since the convolution in the time domain can be replaced by multiplication on the frequency axis, the output x1 (f) of the FFT 12 obtained by expanding x1 (t) in the time domain and the impulse response h (t) are The function h (t) represented by the reference circuit 14a represented above is multiplied by the multiplier 1
4b, the output of the digital compressor 14 becomes data x2 (f) representing x2 (t) on the frequency axis.
Becomes Therefore, the frequency is obtained by measuring the time change of the data x2 (f) with the frequency analyzer 9. With the above configuration, the D / A converter 7 and the distributed delay line 8 can be digitized in addition to the first embodiment.
The compression ratio and the compression width of the compression process can be easily changed.

The embodiments described above can be configured in combination. For example, the D / A converter 7 and the distributed delay line 8 in the configuration of the second embodiment shown in FIG. 4 can be replaced with a configuration in which FIG. 6 of the present embodiment is combined. Further, the D / A converter 7 and the distributed delay line 8 in the configuration of the first embodiment of FIG. 1 may be replaced with the configuration of FIG. 6 of the present embodiment. Further, instead of the D / A converter 7 and the dispersion-type delay line 8 in the configuration of the third embodiment of FIG. 5, it may be combined with FIG. 6 of the present embodiment.

[0020]

As described above, according to the present invention, digital data is finely memorized as one system, and sampling and reproduction are performed at arbitrary intervals to perform specification analysis. Therefore, even if the frequency range of the object to be measured is wide, it can be dealt with. This has the effect that the compression ratio can be easily changed.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of a radio wave specification measuring device according to a first embodiment of the present invention.

FIG. 2 is a sampling data diagram for explaining the operation of the device in the first embodiment.

FIG. 3 is an explanatory diagram of a calculation operation of a pulse width and a pulse repetition period according to the first embodiment.

FIG. 4 is a configuration block diagram of a radio wave specification measuring apparatus according to Embodiment 2 of the present invention.

FIG. 5 is a block diagram illustrating a configuration of a radio wave data measuring apparatus according to Embodiment 3 of the present invention.

FIG. 6 is a block diagram showing a configuration of a radio wave data measuring apparatus according to Embodiment 4 of the present invention.

FIG. 7 is a block diagram showing a configuration of a conventional radio-wave measurement device for frequency analysis.

FIG. 8 is a block diagram showing a configuration of a conventional radio frequency measurement device for frequency and pulse width analysis.

FIG. 9 is a characteristic diagram illustrating the operation of a conventional radio wave specification measuring device.

[Explanation of symbols]

1 antenna, 2 local, 3 mixers, 4 broadband filter, A / D converter, 6 DRFM, 7 D / A converter, 8 distributed delay line, 9 frequency analyzer, 10 sampling period conversion A / D converter, 11 frequency / radio specification analyzer, 12 FFT circuit, 13 radio specification analyzer, 14 digital compressor, 15 sweep local, 1
6 distributor, 17 narrow-band filter, 18 radio wave specification measuring instrument.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenji Tokunaga 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsui Electric Co., Ltd. (72) Inventor Tohru Nonoyama 2-3-2 Marunouchi, Chiyoda-ku, Tokyo 3 Rishi Electric Co., Ltd.

Claims (4)

[Claims] In a configuration in which an input radio wave to be measured is frequency-converted, frequency-analyzed, and pulse-analyzed, an intermediate frequency of the target radio wave after the frequency conversion is converted into an analog signal.
An A / D converter for digital (A / D) conversion, a digital storage unit for sampling and storing the output after the A / D conversion at a first sampling time interval, and reading out the stored sampled value A D / A converter for converting to an analog value, a frequency analyzer for frequency-analyzing the D / A-converted sampling waveform after frequency compression, and a pulse-width detection for sequentially changing the first sampling time. As a time variable, an amplitude waveform analyzed by the frequency analyzer is stored for each pulse width detection time variable value, and a pulse specification analyzer for analyzing a pulse width and a pulse repetition period is provided. A radio wave specification measuring apparatus, wherein a sampling value is subjected to group D / A conversion at a predetermined increasing or decreasing time interval. 2. In digital storage, sampling and storage are performed at a predetermined increase or decrease time interval, and D / D
2. The radio wave specification measuring apparatus according to claim 1, wherein the A conversion is performed at equal intervals. 3. The pulse specification analyzer according to claim 1, wherein the frequency component obtained by subjecting the sampling value stored in the digital storage unit to a fast Fourier transform is used as a time variable for pulse width detection by sequentially changing the first sampling time. 3. The method according to claim 1, wherein an amplitude waveform analyzed by the frequency analyzer is stored for each pulse width detection time variable value, and a pulse width and a pulse repetition period are analyzed. Radio wave specification measuring device. 4. Multiplication of a frequency component obtained by subjecting a sampling value stored in a digital storage unit to a fast Fourier transform, and a reference circuit output having a set reference function after the Fourier transform, in place of the D / A conversion and the frequency compression. The frequency component obtained by subjecting the sampled value stored in the digital storage unit to a fast Fourier transform by using a digital compressor that performs a first sampling time is sequentially changed to a time variable for pulse width detection. 3. The radio wave specification according to claim 1, wherein an amplitude waveform analyzed by the detector is stored for each pulse width detection time variable value, and a pulse width and a pulse repetition period are analyzed. measuring device.